Implantable pressure sensor lead

Abstract

A pressure sensing lead, wherein a hollow needle extending from the distal end of the lead is coupled to a pressure transducer. The hollow needle may be coiled and adapted to be screwed into human tissue, for example through the ventricular septum from the right ventricle into the left ventricle of a patient's heart, or through the wall of the heart into the pericardial sac. Alternatively, the hollow needle may be straight and a separate coiled needle mounted around the straight needle may be provided to affix the lead to body tissue. Pressure gradients are communicated from the tip of the hollow needle to its base and applied to the pressure sensor, allowing, for example, left ventricular pressure measurements to be taken from the right ventricle or pericardial sac pressure measurements to be taken from within the heart without the necessity of the pressure sensor itself passing through the heart wall.

What is claimed is: 
     
       1. A pressure sensor lead comprising: an elongated implantable lead body having proximal and distal ends and having at least one electrical conductor wire therein extending between said proximal and distal ends;   a pressure sensor means for generating an electrical output signal corresponding to pressure applied thereto, said pressure sensor means being disposed near said distal end of said lead and coupled to said at least one electrical conductor wire;   a tissue piercing hollow needle having a base and a tip and an internal lumen, mounted to said pressure sensor means such that lumen serves as means to communicate pressure to said pressure sensor means, wherein said needle is electrically conductive and is electrically coupled to said at least one electrical conductor wire.   
     
     
       2. A pressure sensor lead in accordance with claim 1, wherein said lumen is filled with a pressure-conducting medium. 
     
     
       3. A pressure sensor lead in accordance with claim 2, wherein said pressure-conducting medium is silicone rubber. 
     
     
       4. A pressure sensor lead in accordance with claim 2, wherein said pressure-conducting medium is a non-compressible liquid. 
     
     
       5. A pressure sensor lead in accordance with claim 4, wherein said medium is a saline solution. 
     
     
       6. A pressure sensor lead in accordance with claim 4, wherein said medium is fluid silicone. 
     
     
       7. A pressure sensor lead in accordance with claim 1, wherein a hole is provided in said hollow needle at a point between said base and said tip. 
     
     
       8. A pressure sensor lead according to claim 1 wherein said sensor means comprises a conductive housing and wherein said housing is coupled to said at least one electrical conductor wire. 
     
     
       9. A pressure sensor lead according to claim 1 wherein said at least one conductor wire comprises two mutually insulated electrical conductors. 
     
     
       10. A pressure sensor lead according to claim 1 further comprising a solid, coiled needle mounted to the said pressure sensor means. 
     
     
       11. A pressure sensor lead comprising: an elongated implantable lead body having proximal and distal ends and having an electrical conductor therein extending between said proximal and distal ends;   a pressure sensor means for generating an electrical output signal corresponding to pressure applied thereto, said pressure sensor means being disposed near said distal end of said lead and coupled to said electrical conductor;   a hollow needle having a base and a tip and an internal lumen, mounted to said pressure sensor means such that lumen serves as means to communicate pressure to said pressure sensor means, wherein said hollow needle is a coiled needle.   
     
     
       12. A pressure sensor lead in accordance with claim 11, further comprising a stopper retractably disposed within said coiled needle. 
     
     
       13. A pressure sensor lead in accordance with claim 12, further comprising a spring, coupling said stopper to said pressure sensor means. 
     
     
       14. A pressure sensing lead, comprising: an elongated implantable lead body having proximal and distal ends;   a pressure sensor means for sensing pressure adjacent the distal end of said lead body, said pressure sensor means comprising a hollow needle extendable from the distal end of said lead;   a coiled needle, mounted to said distal end of said lead body, around said hollow needle.   
     
     
       15. A pressure sensing lead according to claim 14, further comprising means for screwing said coiled needle into body tissue. 
     
     
       16. A pressure sensing lead according to claim 15, further comprising means for advancing said hollow needle into said body tissue after screwing said coiled needle into body tissue. 
     
     
       17. A pressure sensing lead according to claim 16 further comprising a flexible tube extending through said elongated lead body and advanceable through said hollow needle.